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VSG-12 Withdrawable Handcart VCB
Withdrawable handcart-type VCB for KYN28 switchgear. Three positions: Service, Test, Isolated. VSG-12 withdrawable handcart VCB is a three-phase indoor vacuum circuit breaker rated at 12kV, designed for drawout installation in medium voltage switchgear. Built to IEC 62271-100, this MV circuit breaker features a handcart trolley with three positions: Service, Test, and Isolated. Rated from 630A to 3150A with short-circuit breaking capacity up to 40kA, the spring operating mechanism supports manual and motor-assisted charging. The withdrawable design enables rapid circuit breaker replacement and live maintenance, making this VCB well-suited for KYN28 switchgear installations in utility substations and industrial power distribution.
- Overview
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VSG-12 Withdrawable Handcart Vacuum Circuit Breaker - 12kV
VSG-12 is the withdrawable handcart configuration of the 12kV vacuum circuit breaker, mounted on a wheeled trolley with isolating contacts for installation in KYN28-12 metal-clad switchgear. It performs the same interruption duty as the fixed VS1-12 but adds the ability to move the breaker between Service, Test and Isolated positions and to remove it entirely from an energised panel.
THE THREE POSITIONS AND WHY THEY MATTER OPERATIONALLY
Service: main isolating contacts engaged, breaker in circuit, ready to carry and interrupt load.
Test: main contacts withdrawn and isolated, control circuits still connected. The breaker can be opened and closed for protection relay testing, trip circuit checking and mechanism verification while the primary circuit stays safely isolated. This is the position where most commissioning and routine testing happens, and it is impossible with a fixed breaker.
Isolated: both power and control circuits disconnected, with the shutter closed over the fixed contacts.
From Isolated the trolley is wheeled clear and a replacement inserted, restoring the feeder in under an hour without de-energising the busbar or disturbing adjacent panels. On a fixed breaker the same job requires a full panel outage.
INTERLOCKING IS THE SAFETY CASE
Mechanical interlocks enforce the correct sequence in hardware rather than relying on procedure. The trolley cannot be racked in or out unless the breaker is open. The earthing switch cannot close while the breaker is racked in. The cable compartment door cannot open until the circuit is earthed. Automatic metal shutters cover the fixed contacts whenever the trolley is withdrawn, so there is no exposed live metal inside the compartment.
VACUUM INTERRUPTION AND ENDURANCE
The arc is extinguished in a sealed chamber below 10-3 Pa. No oil, no SF6, no arc chute maintenance, and no F-Gas obligations. Rated for 30,000 mechanical and 10,000 electrical operations, with ratings from 630A to 3150A and 25kA or 31.5kA breaking capacity.
RETROFIT INTO EXISTING SWITCHGEAR
VSG-12 trolley is dimensionally compatible with VS1, VD4 and equivalent handcart footprints. Where an installed base of KYN28 panels has breakers that the original supplier no longer supports - a common situation across Africa, CIS and the Middle East - a replacement trolley restores the panel at a fraction of the cost of a new switchboard. Send us the panel model, trolley dimensions, pole centre distance and isolating contact arrangement and we will confirm interchangeability before you commit.
MARKET FIT
Serves 11kV Middle East and African networks and 10kV Russian, CIS and Eastern European networks. Saudi Arabian supply verified at 60Hz. Low-temperature grease and anti-condensation heating available for GOST 15150 climatic versions.
PRIMARY APPLICATIONS
- Incomer, bus-section and feeder positions in KYN28-12 withdrawable metal-clad switchgear.
- Utility distribution substations on 10kV and 11kV networks where feeder availability is critical.
- Industrial plant MV switchboards in continuous-process facilities: petrochemical, cement, steel, mining, desalination - where a breaker must be replaceable without shutting the plant.
- Transformer and motor feeder protection in large industrial lineups.
- Generator circuit breaker duty in captive power plants.
- Data centre, hospital and airport MV substations where the electrical safety case requires live-panel maintenance capability.
- Renewable generation collection substations.
- Retrofit replacement of obsolete handcart breakers in aged KYN28 and equivalent switchgear.
WHEN TO CHOOSE WITHDRAWABLE OVER FIXED
Specify VSG-12 handcart when any of the following apply: the feeder cannot tolerate an extended outage for breaker maintenance; protection relays require periodic testing with the breaker operable but isolated; the site has limited technical staff and needs fast module swap rather than in-situ repair; or the client specification mandates withdrawable construction.
Specify the fixed VS1-12 where the panel is fixed-type, the feeder is non-critical, or capital cost governs.
REGIONAL FIT
- Middle East: 11kV networks, with 60Hz verification for Saudi Arabia and witnessed FAT for SEC projects.
- Africa: 11kV networks - fast trolley replacement is particularly valuable where local repair capability is limited.
- Russia and CIS: 10kV networks, GOST R certified, GOST 15150 climatic versions available.
- Eastern Europe: 10kV networks to EN 62271-100.
NOT SUITABLE FOR
Fixed-type panels with no racking rails - specify VS1-12. Outdoor pole-mounted duty - specify ZW32-12. Systems above 12kV - specify VSG-24.
| Category | Item | Specification |
| Compliance | Standards | IEC 62271-100, IEC 62271-200 (withdrawable part), GB/T 1984 |
| Electrical Ratings | Rated voltage | 12 kV |
| Rated frequency | 50 Hz / 60 Hz | |
| Power-frequency withstand (1 min) | 42 kV | |
| Lightning impulse withstand (BIL) | 75 kV peak | |
| Rated normal current | 630 / 1250 / 1600 / 2000 / 2500 / 3150 A | |
| Short-circuit breaking current | 25 kA / 31.5 kA | |
| Short-circuit making current | 63 kA / 80 kA peak | |
| Short-time withstand current | 25 kA / 31.5 kA for 4 s | |
| Operating sequence | O – 0.3s – CO – 180s – CO | |
| Withdrawable System | Trolley positions | Service / Test / Isolated |
| Racking | Manual screw racking standard; motorised optional | |
| Isolating contacts | Silver-plated tulip contacts, rating matched to breaker | |
| Shutters | Automatic metal shutters covering fixed contacts when withdrawn | |
| Interlocks | Breaker-open before racking; earthing switch & cable door interlocked | |
| Control circuit | Secondary plug disconnected in Isolated; connected in Test & Service | |
| Endurance | Mechanical life | ≥30,000 operations |
| Electrical life at rated current | ≥10,000 CO operations | |
| Opening time | 30–60 ms | |
| Closing time | 40–80 ms | |
| Operating Mechanism | Type | Spring stored-energy (VSG series) |
| Spring charging motor | AC/DC 110 V or 220 V | |
| Manual charging | Provided as backup | |
| Closing coil | DC 110 V / 220 V | |
| Shunt trip coil | DC 110 V / 220 V | |
| Auxiliary switch | Up to 13NO+13NC | |
| Anti-pumping | Mechanical and electrical | |
| Mechanical | Pole centre distance | 210 mm |
| Trolley compatibility | VS1, VD4 and equivalent KYN28 handcart footprints | |
| Weight (approx.) | 130 kg (630 A) – 190 kg (3150 A) including trolley | |
| Service Conditions | Ambient temperature | −30 °C to +55 °C |
| Altitude | ≤1000 m standard; ≤2000 m on request with derating | |
| Relative humidity | Daily average ≤95% |
OPTIONS
Motorised racking for remote or SCADA operation | second shunt trip coil | under-voltage release | additional auxiliary contacts | operations counter | position indication contacts for Service/Test/Isolated | low-temperature grease for GOST 15150 versions | retrofit trolley to customer panel dimensions
PRE-SALES SELECTION
- Application review against your duty: rated current, breaking capacity, operating sequence, and expected switching frequency.
- Retrofit and replacement sizing. Send us the existing unit's model, pole-centre distance and mounting dimensions and we will confirm interchangeability before you order.
- Grid verification: 12kV class for 10kV (Russia/CIS) and 11kV (Middle East/Africa) networks; 24kV for 20kV and 22kV; 40.5kV for 35kV. Saudi Arabian supply verified at 60Hz.
- Coil, motor and auxiliary-contact configuration specified to your control voltage (AC/DC 110V or 220V) and SCADA interface requirement.
- Low-temperature variants with cold-rated grease and anti-condensation heating for CIS winter service.
MARKET ACCESS AND DOCUMENTATION
- Type-test reports to IEC 62271-100 / IEC 62271-102 / IEC 62271-103 as applicable, issued with the shipment.
- Third-party certification (KEMA, ASTA, CESI, TUV) available where tender documents require witnessed evidence rather than a manufacturer's report.
- Certification support for SASO SABER, SONCAP, KEBS PVoC, ICIGI and GOST R submissions, including HS-code classification (Nigeria has required 10-digit HS codes since March 2025).
TESTING AND DELIVERY
- 100% routine testing before dispatch: power-frequency withstand, contact resistance, mechanical characteristic curve, timing test, and auxiliary circuit verification.
- Individual test report supplied per serial number.
- Export packing with desiccant and moisture barrier; palletised for consolidated shipment.
- Documentation: routine test report, type-test certificate, dimensional drawing, wiring schematic, O&M manual, spare parts list.
AFTER-SALES
- Installation and commissioning guidance, remote support or engineer dispatch.
- Maintenance training covering mechanism inspection, contact wear measurement and vacuum interrupter integrity testing.
- Wear parts (coils, contacts, mechanism components) held in stock for rapid replacement.
- Technical response within 24 hours; multilingual manuals in English, Russian, French and Arabic.
- Warranty: 18 months from delivery or 12 months from commissioning, whichever expires first.
TYPE TESTING
- Type tested to the applicable IEC standard - IEC 62271-100 for circuit breakers, IEC 62271-102 for earthing switches and disconnectors, IEC 62271-103 for load break switches.
- Verified for rated short-circuit breaking and making capacity, short-time withstand current, power-frequency and lightning impulse withstand, temperature rise, and mechanical endurance across the full rated operating sequence.
- Third-party certification from KEMA, ASTA, CESI or TUV available where the tender requires witnessed evidence.
VACUUM INTERRUPTER CONTROL (where applicable)
- Every interrupter is vacuum-integrity tested before assembly; vacuum degradation is the dominant failure mode in a VCB and is not visible externally once installed.
- Contact stroke, over-travel and contact wear allowance measured and recorded per pole.
- Interrupters sourced only from qualified manufacturers with batch traceability.
IN-PROCESS INSPECTION
- Insulating components partial-discharge tested before assembly.
- Mechanism spring force and charging characteristic verified against specification.
- Pole-centre distance and mounting interface dimensions checked against drawing - critical for retrofit interchangeability.
- Plating thickness on current-carrying contacts verified per batch.
ROUTINE TESTING - 100%, NO SAMPLING
- Power-frequency withstand voltage across the open contacts and to earth.
- Main circuit contact resistance measurement.
- Mechanical characteristic curve: closing time, opening time, contact bounce, and three-phase simultaneity.
- Operating mechanism function at minimum, rated and maximum control voltage - a unit that only operates at nominal voltage will fail during a real disturbance when station battery voltage sags.
- Auxiliary switch continuity and position signalling verification.
- Serialised routine test report issued with every unit.
TRACEABILITY AND SYSTEM
- ISO 9001 quality management system.
- Serial number traceability to vacuum interrupter batch, mechanism batch and insulation component batch.
- Test records retained for the warranty period and available on request.
ENVIRONMENTAL QUALIFICATION
Where the destination environment exceeds IEC reference conditions we qualify against it: elevated-ambient temperature-rise verification for Gulf service, salt-spray testing for coastal sites, and low-temperature operation verification with cold-rated lubricant for GOST 15150 climatic versions.
